This invention relates to a heddle for a weaving machine, and more particularly to such a heddle having a thread eye portion which provides for easier passing of the warped threads therethrough while at the same time permitting easier and smoother passage of the adjacent warp threads past the adjoining heddles.
Known heddles are typically made of strip steel supported at opposite ends on heddle frames of a weaving machine. The heddles are supported in such manner that the major plane of the heddle is parallel to the course of the warp thread. Since the warp thread must be guided by the heddle, it is provided with a thread eye which, however, oftentimes presents a problem since the heddle is disposed incorrectly as soon as it is strung on the heddle frame. The correct relationship of the heddle to the warp thread would be perpendicular.
Since it is not possible to guide the warp threads through the plane of the strip steel of the heddle, the heddle must be deformed in the region of the thread eye to enable the passage of the warp thread therethrough.
There are two types of such deformation; twisting or rotation, and crossed or corrugated. The rotation of the thread eye portion relative to the plane of the strip typically lies in a plane rotated 25.degree. to 30.degree. about the central axis of the heddle. In the so-called crossed mode of deformation, the opposed legs comprising the thread eye are pulled apart to enable the passage of the warped thread.
Both deformation modes have their advantages and drawbacks. The rotated style offers the warped thread a relatively good thread support in the thread eye, a feature that has the effect of preserving the thread. However, the adjacent warp threads must slide over a wider area over the protruding edges of the rotated portion. Thus, as the rate of weaving increases, this creates a problem.
The warp threads of the crossed mode must also slide over the edges, but the region is significantly shorter than compared to that of the rotated mode. However, the height of the detoured path of the warp thread is somewhat greater such that thread deflection occurs suddenly. Moreover, with such crossing of the thread eye no real support is offered to the thread but rather there is a tendency to pinch the thread.
With both types of thread eye construction the adjacent warp threads must rotate the heddle by a certain amount out of its original plane, in order to create a sufficiently unobstructed passage both for the warp thread in the thread eye and the adjacent threads.
Japanese Patent No. 59-199834 discloses a heddle which is formed by first rotating the region of the thread eye with the opposed legs forming the eye being deformed back again into parallel relationship to the passing thread. So that the thread can pass through, a greater rotation must be carried out with the result that when the legs are deformed back again into a parallel position, the legs project by a relatively significant amount to the side.
U.S. Pat. No. 997,283 discloses side legs at the heddle eye portion as being displaced crosswise first and then the heddle deformed in the region of the thread eye. This results in a similar drawback as when the thread eye is only rotated and where the beveled segments protrude on the sides, thus possibly damaging the adjacent warp threads.
Because of recent developments in the use of microfibre yarns, together with the increase in the rate of weaving, the aforenoted problems are heightened together with a decline in efficiency thus resulting in increased costs rendering the yarn processing operation less efficient and less profitable. The aforedescribed types of heddles with their thread eye designs have also contributed to a significant share of these problems.